1. Field of the Invention
The present invention relates to a flip chip type light-emitting element formed with a III-group nitride semiconductor, and more particularly to a flip chip type light-emitting element having a feature in the form of an electrode.
2. Description of the Related Art
In recent years, various techniques are made use of to suppress unevenness in light transmission by uniformly supplying an electric current to a light-emitting layer in the flip chip type light-emitting element formed with the III-group nitride semiconductor.
For instance, as a technique for improving the diffusion characteristics of a current to a light-emitting layer, a technique that an n layer is exposed in a comb-tooth shape and an n type contact electrode is provided in the exposed part is disclosed in Patent Documents 1 and 2. Further, Patent Documents 2 and 3 disclose a technique that a light transmission electrode is provided on the entire surface of a p layer to diffuse a current to the p layer from a pad electrode by the light transmission electrode. Further, Patent Documents 1 and 3 disclose a technique that a plurality of pad electrodes are provided on a p electrode to improve diffusion characteristics of a current to the p electrode from the pad electrodes.
Further, Patent Document 4 discloses a technique that a metal film is provided in an insulating protective film with which the surface of a III-group nitride semiconductor layer is covered to improve a reflection factor.    Patent Document 1: JP-A-2001-203386    Patent Document 2: JP-A-2003-524295    Patent Document 3: JP-A-2005-197289    Patent Document 4: JP-A-11-340514
However, in the flip chip type light-emitting element having a light transmission electrode on the surface of a p layer and a plurality of pad electrodes provided on the light transmission electrode, a problem arises that since the areas of the pad electrodes are small, an electric current is concentrated on the contact parts of the pad electrodes and the light transmission electrode to deteriorate the light transmission electrode.